How to resize 480p videos

[Hakabane_]

Sorry, my English is not perfect.
Hi guys, I have a query, maybe someone already has experience with a problem like this.
I want to convert a video from 480p to 720p or 1080p without losing quality.
Before anything the anime that I want to use is very old and little known so there is no better quality than 480p.
I already probe with both editors, vegas and premiere using distindos "soft image" and different software that supposedly improves the quality and others like Avidemux, Wondershare, VReveal, etc. In addition to trying to work in different ways with its original H264 file but the final video comes out pixelated and looks horrible.
Suggestions or recommendations?

Spanish
Hola muchachos tengo una consulta, quizá alguien ya tiene experiencia con un problema asi.
quiero convertir un video de 480p a 720p o 1080p sin perder calidad.
antes que nada el anime que quiero usar es muy antiguo y poco conocido por lo cual no existe una mejor calidad que 480p.
Ya probe con ambos editores, vegas y premiere usando distindos "suavizados de imagen" y distintos softwares que supuestamente te lo mejoran la calidad y demas como ser Avidemux, Wondershare, VReveal, etc. ademas de que trate de trabajar de distintas formas con su archivo original H264 pero el video final sale pixeleado y se ve horrible.
Sugerencias o recomendaciones?

[Scintilla]

I wouldn't recommend this unless you're trying to mix 480p sources with bigger ones in the same AMV. I believe IIP (by Didée, I think?) is one of the best-known AVISynth filters for this kind of upscaling.

Or at least it was 10+ years ago when I was still in the loop with AVISynth filtering developments.

[Kionon]

I've successfully used Avidemux filters in combination to radically improve a bad 480p source to 720p or 1080p upscale that actually looks superior to the original 480p, but it takes a lot of experimentation. You can do even more with AviSynth, and perhaps now with VaporSynth. It also takes layering various filters in the proper order to get the best look. If you would like to see something I have done recently you can see what I managed with the R1 Robot Girl DVDs here: viewtopic.php?f=2&t=127545

[Kireblue]

l33tmeatwad put together a avisynth script that upscales pretty well.
http://www.l33tmeatwad.com/scripts/anime-upscale